Which of the Following Is the Best Example of Classical

Which of the following is the best example of classical conditioning?

A) Julia develops a fear of public speaking because some of Julia's classmates snicker when she asks questions about math.
B) Samantha covers her work whenever the teacher begins to walk around the room because, in the past, the teacher had a tendency to stop at Samantha's desk, lean over her shoulder, and sigh.
C) Alan is afraid of water because he never learned how to swim, and one of Alan's friends almost drowned last summer.
D) Martin takes the long way home after school because he likes to stop at the bookstore and browse through the comic books.